Cropping metal sections to length

ABSTRACT

A method of cropping a red-hot bloom by televising the end surface of the bloom and evaluating from the image the amount by which the bloom should be cropped back in dependence on any irregularities shown so as to produce a bloom sound throughout its length. Cropping back by the requisite amount may be effected in a number of successive stages.

United States Patent [191 Goodchild et a1.

[ CROPPING METAL SECTIONS TO LENGTH [75] Inventors: Keith Trevor Goodchild; Harold Edward Merrill, both of Wolverhampton, England [73] Assignee: British Steel Corporation, London,

England [22] Filed: Dec. 27, 1972 [21] App]. No.: 318,905

[30] Foreign Application Priority Data Dec. 28, 1971 Great Britain 60265/71 [52] US. Cl 83/42, 83/288, 83/371, 83/580 [51] int. C1 826d 7/00 [58] Field Of Search 83/13, 285-289,

[ June 4, 1974 [56] References Cited UNITED STATES PATENTS 1,959,851 5/1934 Biggert, Jr. .4 83/289 3,354,658 11/1967 Leonardi 1 14/168 X 3,543,620 12/1970 Hilsanseck 83/416 X Primary ExaminerJ. M. Meister Attorney, Agent, or Firm-Bacon & Thomas [57 Q ABSTRACT A method of cropping a red-hot bloom by televising the end surface of the bloom and evaluating from the image the amount by which the bloom should be cropped back in dependence on any irregularities shown so as to produce a bloom sound throughout its length. Cropping back by the requisite amount may be effected in a number of successive stages.

8 Claims, 5 Drawing Figures CROPPING METAL SECTIONS TO LENGTH This invention relates to a method of cropping a rolled metal section to length, and more particularly relates to a method of optimising the cropped length, i.e., cropping back the metal section by a minimum amount so as just to remove any irregularities produced by casting etc. whereby to produce the maximum length which is usable and sound throughout.

Hitherto, in such operations a standard length is usually cropped off the ends of the section which is nominally calculated to remove all such irregularities in say, 95 percent of the sections so treated. Clearly however, any such rule-of-thumb method must result in many lengths being cropped back by an amount much more than is necessary, resulting in wastage of material, and it is an object of this invention to provide a more accurate degree of control over end cropping.

The invention is particularly but not necessarily exclusively related to cropping red-hot steel sections in a Primary Mill.

From one aspect, the present invention provides a method of cropping to length an incandescent pliant rolled metal section by forming a televised image of the end surface of the section, evaluating from the image the amount by which the section should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount whereby to produce a section sound throughout its length.

Cropping back by the requisite amount may be affected in a number of successive stages with a fresh evaluation at each stage to improve the accuracy of the technique and minimise the discard.

The metal section may be a killed, i.e. de-oxidised, steel bloom.

The television system may include a camera sited adjacent to the crop shears in a Primary Mill with a high magnification zoom lens aimed at the end surface of the bloom, and the television equipment may be optically or thermally (infra-red) responsive.

Preferably, means are provided for adjusting the contrast of the screened image whereby to facilitate the indentification of irregularities. More particularly piping, segregation and inclusions present in the bloom may be identified by this technique.

In accordance with this invention then, bloom cropping can be optimised by this video inspection technique, the operator or shearman evaluating the image of the end surface to determine the amount by which the bloom should be cropped, thus avoiding the wastage hitherto experienced in cropping by a standard statistically evaluated pre-set amount. Meredirect visual inspection of the red-hot bloom is impracticable because of the response of the human eye and this cannot be compensated for by optical filters to achieve the necessary degree of contrast. Accessibility is a further problem and the accuracy with which a bloom may be brought up to a datum position has hitherto frequently been aggravated by parallax errors introduced-as a result of the siting of the operators pulpit in relation to the crop shear.

Although the invention is primarily of use in top cropping i.e., cropping the top of a rolled ingot where the irregularities are most predominant it may also be of use in bottom cropping i.e. the end since the cropped piece or discard is viewed as it lies on the shear before being dispensed by the pusher. Thus if the standard amount by which this end is cropped is insufficient then this will be apparent.

In order that the present invention may be fully understood one embodiment thereof will now be described with reference to two specific examples of typical images of cropped bloom ends with reference to the accompanying drawings in which:

FIG. 1 schematically illustrates a crop shear station in a Primary Mill with the television equipment appropriately sited.

FIGS. 2A and 3A illustrate typical images of a cropped bloom end; and

FIGS. 28 and 3B illustrate sections along I-I and lI-ll in FIGS. 2A and 3A respectively.

Referring now to FIG. 1 a red-hot rolled killed steel bloom 4 is shown advancing along rollers 5 towards a crop shear station schematically indicated at 6. A television camera 7 has a zoom lens 8 aimed at and focussed on to the end surface of the bloom at a reference position at which the bloom is arrested between the shears. The video signal from the camera is transmitted via a cable 9 to a television receiver 10 in the shearmans pulpit, the image of the end surface being manifested as an end-on image on a screen 11. The a camera and/or receiver embodies controls (not shown) for adjusting contrast, sensitivity etc.

When the bloom arrested at the reference position the shearman observes the image of the end surface and evaluates the type and extent of any irregularity and estimates the depth of cut required to crop the end clean. The bloom is advanced accordingly along the rollers and the end sheared-off. If any irregularities remain then the process is repeated and indeed the shearing may be effected in several discrete attempts since clearly a more accurate estimation of the depth of cut I required can be made in this manner, albeit at the expense of time.

This operation or top cropping, so called because it is effected on the end which was the top of the ingot, may be repeated on the other end bottom cropping. The difference here however is that the end observed is the discard as it remains on the shear before being pushed aside. Normally bottom cropping is effected for purely mechanical reasons since the bottom of the ingot is not subject to the effects manifested at the top; accordingly, a standard preset amount of the order of 2 percent of the bloom length is normally cropped off. Thus, if this procedure is still adopted the present method will merely enable one to recognise when the standard bottom crop is insufficient.

Referring now to FIGS. 2A to 3B typical images are shown of a top cropped end after it has been subjected to an initial cut. In both cases the effects are apparent in the lower half of the bloom surface by reason of the deforming shearing action from above.

In FIG. 2A discrete bright areas 12 appearing on the image are representative of large shallow surface cavities and the shaded portions 13 are representative of the shearing overlap. The darker areas 14 further towards the centre are indicative of cavities present which extend beyond the surface (piping). The shaded areas 15 are simply indicative of differential cooling.

FIG. 2B, which is a section along I-l in FIG. 2A, illustrates these effects within the bloom.

FIGS. 3A and 3B show similar irregularities, like reference numerals being employed to indicate the same type of defect or effect as in the previous Figures.

In general, the effects of pipe, segregation and inclusions can readily be detected and evaluated by visual observation of the screened image with appropriate adjustment of the contrast control. Inclusions in particular are apparent by reason of their emissivity being greater than that of the steel, i.e., the non-metallic material of slag origin is either molten or at least very plastic at the cropping temperature. Such non-metallic inclusions are furthermore smeared or exuded over the surrounding surface exposed upon cropping, accentuating the effect observed and contributing towards surface cavities. Thin slivers of such inclusions also appear on the surface as this material migrates to the surface by reason of the central porosity of the bloom.

Although this invention has been described and illustrated with reference to the particular embodiment illustrated it is to be understood that various alterations of modifications could readily be made without departing from the scope of this invention. For example, as mentioned above, a thermally instead of an optically responsive television system may be employed and the method may be fully automated, e.g., a computer may evaluate the image whilst a dependent control system may advance the bloom and crop the end appropriately.

We claim:

1. A method of cropping to length an incandescent pliant rolled metal section by forming an end-on tele vised image of the end surface of the section, evaluating from the image the amount by which the section should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount whereby to produce a section sound successive stages with a fresh evaluation at each stage.

3. A method according to claim 2, in which the contrast of the televised image is adjustable whereby to facilitate the identification of irregularities.

4. A method according to claim 3, in which the televised image is derived from equipment optically or thermally responsive.

5. A method of cropping to length a red hot steel bloom by forming an end-on optically televised image of its end surface, evaluating from the image the amount by which the bloom should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount whereby to produce a bloom sound throughout its length.

6. A method according to claim 5, in which the cropping back by the requisite amount is effected in a number of successive stages with a fresh evaluation at each stage, the cropping being effected at the top and bottom end of the bloom.

7. A method of cropping to length a red hot deoxidised steel bloom by forming an end-on optically televised image of its end surface, evaluating from the image the amount by which the bloom should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount in one or more successive stages whereby to produce a bloom sound throughout its length, a fresh evaluation being made at each stage.

8. A method according to claim 3 in which the televised image is derived from equipment thermally re- 

1. A method of cropping to length an incandescent pliant rolled metal section by forming an end-on televised image of the end surface of the section, evaluating from the image the amount by which the section should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount whereby to produce a section sound throughout its length.
 2. A method according to claim 1, in which cropping back by the requisite amount is effected in a number of successive stages with a fresh evaluation at each stage.
 3. A method according to claim 2, in which the contrast of the televised image is adjustable whereby to facilitate the identification of irregularities.
 4. A method according to claim 3, in which the televised image is derived from equipment optically or thermally responsive.
 5. A method of cropping to length a red hot steel bloom by forming an end-on optically televised image of its end surface, evaluating from the image the amount by which the bloom should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount whereby to produce a bloom sound throughout its length.
 6. A method according to claim 5, in which the cropping back by the requisite amount is effected in a number of successive stages with a fresh evaluation at each stage, the cropping being effected at the ''top'' and ''bottom'' end of the bloom.
 7. A method of cropping to length a red hot de-oxidised steel bloom by forming an end-on optically televised image of its end surface, evaluating from the image the amount by which the bloom should be cropped back from that surface in dependence on any irregularities shown, and cropping back by that amount in one or more successive stages whereby to produce a bloom sound throughout its length, a fresh evaluation being made at each stage.
 8. A method according to claim 3 in which the televised image is derived from equipment thermally responsive. 